﻿var LunarDaysOfMonth = new Array
(
0xd4a8, 0xd4a0, 0xda50, 0x5aa8, 0x56a0, 0xaad8, 0x25d0, 0x92d0, 0xc958, 0xa950, // 2001-2010 
0xb4a0, 0xb550, 0xb550, 0x55a8, 0x4ba0, 0xa5b0, 0x52b8, 0x52b0, 0xa930, 0x74a8, // 2011-2020 
0x6aa0, 0xad50, 0x4da8, 0x4b60, 0x9570, 0xa4e0, 0xd260, 0xe930, 0xd530, 0x5aa0, // 2021-2030 
0x6b50, 0x96d0, 0x4ae8, 0x4ad0, 0xa4d0, 0xd258, 0xd250, 0xd520, 0xdaa0, 0xb5a0, // 2031-2040 
0x56d0, 0x4ad8, 0x49b0, 0xa4b8, 0xa4b0, 0xaa50, 0xb528, 0x6d20, 0xada0, 0x55b0 // 2041-2050 
);

// 数组LunarLeapYear存放农历2001年到2050年闰月的月份，如没有则为0，从高到低，每字节存两年 
var LunarLeapYear = new Array
(
0x40, 0x02, 0x07, 0x00, 0x50, // 2001-2010 
0x04, 0x09, 0x00, 0x60, 0x04, // 2011-2020 
0x00, 0x20, 0x60, 0x05, 0x00, // 2021-2030 
0x30, 0xb0, 0x06, 0x00, 0x50, // 2031-2040 
0x02, 0x07, 0x00, 0x50, 0x03 // 2041-2050 
);


// 返回农历iLunarYear年的闰月月份，如没有则返回0 
function GetLeapMonth(iLunarYear) {
    var Leap = LunarLeapYear[(iLunarYear - 2001) >> 1];
    return (((iLunarYear - 2001) & 1) == 0) ? (Leap >> 4) : (Leap & 0x0f);
}

// 返回农历iLunarYer年iLunarMonth月的天数，结果是一个长整数
// 如果iLunarMonth不是闰月， 高字为0，低字为该月的天数
// 如果iLunarMonth是闰月， 高字为后一个月的天数，低字为前一个月的天数
function LunarMonthDays(iLunarYear, iLunarMonth) {
    var High;
    var Low;
    var Bit;

    High = 0;
    Low = 29;
    Bit = 16 - iLunarMonth;
    if ((iLunarMonth > GetLeapMonth(iLunarYear)) && (GetLeapMonth(iLunarYear) > 0)) Bit--;
    if ((LunarDaysOfMonth[iLunarYear - 2001] & (1 << Bit)) > 0) Low++;
    if (iLunarMonth == GetLeapMonth(iLunarYear)) {
        High = ((LunarDaysOfMonth[iLunarYear - 2001] & (1 << (Bit - 1))) > 0) ? 30 : 29;
    }

    return Low + (High << 16);
}

// 返回农历iLunarYear年的总天数
function LunarYearDays(iLunarYear) {
    var Days;
    var tmp;

    Days = 0;
    for (var i = 1; i <= 12; i++) {
        tmp = LunarMonthDays(iLunarYear, i);
        Days = Days + ((tmp >> 16) & 0xffff); //取高位 
        Days = Days + (tmp & 0xffff); //取低位 
    }

    return Days;
}

// 将农历iLunarYear年格式化成天干地支记年法表示的字符串 
function FormatLunarYear(iLunarYear) {
    var szText1 = new String("甲乙丙丁戊己庚辛壬癸");
    var szText2 = new String("子丑寅卯辰巳午未申酉戌亥");
    var strYear;

    strYear = szText1.substr((iLunarYear - 4) % 10, 1);
    strYear = strYear + szText2.substr((iLunarYear - 4) % 12, 1);

    return strYear + "年";
}

// 将农历iLunarMonth月格式化成农历表示的字符串
function FormatLunarMonth(iLunarMonth) {
    var szText = new String("正二三四五六七八九十");
    var strMonth;

    if (iLunarMonth <= 10) {
        strMonth = szText.substr(iLunarMonth - 1, 1);
    }
    else if (iLunarMonth == 11) strMonth = "十一";
    else strMonth = "十二";

    return strMonth + "月";
}

// 将农历iLunarDay日格式化成农历表示的字符串
function FormatLunarDay(iLunarDay) {
    var szText1 = new String("初十廿三");
    var szText2 = new String("一二三四五六七八九十");
    var strDay;
    if ((iLunarDay != 20) && (iLunarDay != 30)) {
        strDay = szText1.substr((iLunarDay - 1) / 10, 1) + szText2.substr((iLunarDay - 1) % 10, 1);
    }
    else if (iLunarDay != 20) {
        strDay = szText1.substr(iLunarDay / 10, 1) + "十";
    }
    else {
        strDay = "二十";
    }

    return strDay;
}

// 将公历日期转换为农历日期，返回农历表示的字符串
function GetLunarDateString(SolarDate) {
    var tmp;
    var iLunarYear;
    var iLunarMonth;
    var iLunarDay;
    var Leap = false;
    var MinMilli = 1000 * 60;
    var HrMilli = MinMilli * 60;
    var DyMilli = HrMilli * 24;

    // 从2001年1月1日算起，给定的公历日期已经过去的天数
    // 11323是1970年1月1日到2001年1月1日之间的天数，因为Date是从1970年1月1日作为起点的
    var iSpanDays = Math.round(SolarDate.getTime() / DyMilli) - 11323;

    // 公历2001年1月24日为农历2001年正月初一，差23天
    if (iSpanDays < 23) {
        iYear = 2000;
        iLunarMonth = 12;
        iLunarDay = iSpanDays + 7;
    }
    else {
        // 从农历2001年正月初一算起 
        iSpanDays = iSpanDays - 23;
        iLunarYear = 2001;
        iLunarMonth = 1;
        iLunarDay = 1;

        // 计算农历年 
        tmp = LunarYearDays(iLunarYear);
        while (iSpanDays >= tmp) {
            iSpanDays -= tmp;
            iLunarYear++;
            tmp = LunarYearDays(iLunarYear);
        }

        // 计算农历月 
        tmp = LunarMonthDays(iLunarYear, iLunarMonth) & 0xffff; //取低字
        while (iSpanDays >= tmp) {
            iSpanDays -= tmp;
            if (iLunarMonth == GetLeapMonth(iLunarYear)) // 该年该月闰月
            {
                tmp = LunarMonthDays(iLunarYear, iLunarMonth) >> 16; //取高字
                if (iSpanDays < tmp) {
                    Leap = (tmp > 0) ? true : false; // 闰月的后个月？
                    break;
                }
                iSpanDays = iSpanDays - tmp;
            }

            iLunarMonth++;
            tmp = LunarMonthDays(iLunarYear, iLunarMonth) & 0xffff; //取低字
        }

        // 计算农历日 
        iLunarDay += iSpanDays;
    }

    return FormatLunarYear(iLunarYear) + (Leap ? "闰" : "") + FormatLunarMonth(iLunarMonth) + FormatLunarDay(iLunarDay);
}
//检查输入时间格式是否正确
function CheckDT(str) {
    var r = str.match(/^(\d{1,4})(-|\/)(\d{1,2})\2(\d{1,2})$/);
    if (r == null) {
        return false;
    }
    else {
        if (parseInt(r[1]) < 1903) return false;
        
        var d = new Date(r[1], r[3] - 1, r[4]);
        return (d.getFullYear() == r[1] && (d.getMonth() + 1) == r[3] && d.getDate() == r[4]);
    }
}

